Filament mount testing apparatus



Feb. 28, 1956 L. E. DILTS FILAMENT MOUNT TESTING APPARATUS Filed Feb. 23, 1951 3d Inv en tor Lee E.DiLts, 3 W 6 K His A t tor'nes.

limited States Patent l 2,736,194 FILAMENT MOUNT TESTINGAPPARATUS Lee E. Dilts, South Euclid, Ohio, assignor to General Electric Company, a corporation of New York Application February 23, 1951, Serial No. 212,279

Claims. (Cl. 73-88) My invention relates to apparatus for testing the filament mounts of flash lamps, incandescent lamps and similarly constructed electrical devices. More particularly, my invention relates to apparatus for testing the security of the filament-to-lead connections and the con tinuity of the filament of such mounts.

The manufacture of filament mounts for many electrical devices comprises the step'of fastening short lengths of very fine wire to the free ends of metal leads extending from a stem and entails the making of uniformly low resistance connections between the filament wire and the leads in order to give uniform operating properties to said electrical devices. The shortness, often /s inch, and the fineness, often .0007 inch diameter, of the filament wire cause difficulty in both the handling and connecting operations inasmuch as any variance in the mounting apparatus may rupture the filament and may produce a loose or high resistance filament-to-lead connection. It has been proposed in Patent 2,329,599 to J. Flaws, dated September 14, 1943, and assigned to the assignee of this present invention, that the filamentto-lead connections be tested by applying pressure against the leads in a direction parallel to the filament wire so as to cause the leads to be separated and pulled from the filament wire if the connection is loose and therefore of higher than normal resistance. The displacement of the leads, which also occurs when a broken filament is encountered, is used to eifect operation of a signal and control means to be set in motion when a defective mount is discovered.

An object of my invention is to provide apparatus for applying accurately determined pressures against a lead of a mount so as to allow the maximum testing force thereagainst and still avoid excessive pressure on occasion which will rupture the filament wire. My invention is particularly applicable to the testing of flash lamps and flash light lamp mounts wherein extremely small and fragile filaments for use with dry cell batteries are provided. Another object of my invention is to provide apparatus for attempting to spread the leads of a mount with an accurately determined force and, should the leads spread, for effecting operation of an electric signal and electrically operated control means.

in apparatus of this nature heretofore employed, the separating pressure against the leads is applied by spring tension in such a way that the more the leads are spread the less the tension. A feature of my invention is the provision of means, preferably permanent magnets, such that the more the leads are spread the more the tension is increased.

Still other objects and advantages of my invention will appear from the following detailed description of a species thereof and from the accompanying drawing.

in the drawing, Fig. 1 is a perspective view of test apparatus comprising my invention, the apparatus being located at an advanced position in operative relation to a hash lamp mount retained by a' head of associated apparatus; Fig. 2 is a plan view on a larger scale of the test apparatus at its initial position in relation'to the leads of a mount; Fig. 3 is a vertical section through a center portion of the apparatus in the direction and substantially as indicated by the line and arrows 3-3 in Fig. 2; and Fig-4 is a wiring diagram of electrical means associated with the apparatus.

The test apparatus 1 disclosed in the drawing is located to one side of the position occupied by the lamp mount 2 and in the course of the cycle of operation is advanced horizontally to operative relation to said mount 2 and then retracted. This manner of operation permits the test apparatus to be associated with automatic means, in the present instance the head 2', for

advancing the mount 2 to a definite relation thereto and also permits said apparatus to function as one of the automatic means located at a work station of the mountmaking machine disclosed in Patent 1,907,532 to J. Flaws, dated May 9, 1933, and in such instances is preferably operated by said machine in the manner of the apparatus thereof in order to be synchronized with the movements of the mount carrier and the presentation of successive mounts.

The initial step in the cycle of operation of the test apparatus 1 is a positioning movement thereof advancing the tips of the test fingers 3 and 4 between the leads 5 and 6 of the mount 2 at an elevation just above the filament 7, which brings the apparatus into operative relation to the mount 2 which remains at one position throughout the operation thereof. The advance of the test fingers 3 and 4 results from a corresponding movement of the levers 8 and 9, the supporting means therefor, and is eiiected by the forward movement (Fig. l) of the sub-base member or slide 10 in the ways of a base member or bracket 11 extending from an adjacent portion of the machine frame (not shown). At that time, the tips of the test fingers 3 and 4 occupy a minimum of space as the levers 8 and 9, which pivot on the upstanding studs 12 and 13 respectively on the top surface of the slide 10, are turned about said studs 12 and 13 to positions where said tips are back-to-back. This arrangement of the levers 8 and 9 exists because of the presence of the wedge 14 between the rollers 15, 16 on the lower surface of said levers 8 and 9 and is maintained during the advancing movement since the push rod 17, the support for said wedge 14, is held where the shank 18 thereof bears against the cross strap 19 on the slide 10 by the expansion force of the helical spring 20. The initiating force for the advance or positioning movement of the apparatus originates in main drive means (not shown) of the type used in lamp manufacturing apparatus (see Flaws Patent 1,907,532 hereinbefore referred to, for instance) and effects -a longitudinal displacement of the push rod 17 by means of a rocking motion of the operating lever 21 about the pivot pin 22 in the bracket 11 under the influence of the connecting rod 23.

The test operation of the apparatus occurs directly after the positioning movement thereof when the test fingers 3 and 4 are caused to spread and engage the leads 5 and 6. At that time, the motion in the slide 10 is interrupted by the engagement of a screw 24 on a laterally projecting car 25 of said slide 10 with a stationary stop 26 on the bracket 11 and the further forward motion of said push rod 17, effecting a compression of the spring 20, withdraws the wedge 14 from between the rollers 15 and 16 on the levers 8 and 9 respectively. The spreading motion of the test fingers 3 and 4 is effected by the mutual attraction of magnets 27 and 28 located in the remote ends of the levers 8 and 9, respectively, and having opposed faces of opposite polarity. The attraction of magnets 27 and 28 causes levers 8 and 9 to be pivoted to press said test fingers 3 and 4 against the leads 5 and 6 withia Patented Feb. 28, 1956 force of sufficient strength to pull said leads 5 and 6 out of position, should the filament 7 be broken or should it be attached to either lead 5 or 6 by a connection of subnormal strength.

The force with which the fingers 3 and 4 tend to disrupt the mount 2 is accurately determinable in every cycle of operation of the apparatus and remains constant over a considerable period of time because the strength of the magnets 27 and 28 does not change appreciably, and because the pivots provided for the levers 3 and 9 can be relatively frictionless and can easily be kept in proper operating condition.

The specific test used in each instance depends on the construction and type of mount 2 since the ultimate strength of the filament 7 and stiffness of the leads 5 and 6 are factors to the establishment of a satisfactory test and is dependent on the relation of the magnets 27 and 28 at the time the test lingers 3 and 4 are caused to bear against the leads 7 and 8. For this reason, the magnets 27 and 28 are clamped in the slotted end portions of the levers 8 and 9 by the screws 29, 29 during all normal periods of operation of the apparatus but can be repositioned in said levers 8 and 9, after the screws 29, 29 have been loosened, should it be desirable to change the, test conditions. An adjusting screw 30 in a wing of lever 8 is also provided to assist in making very fine adjustments of magnet 27 toward the magnet 28. This latter feature of the apparatus is a desirable advantage particularly because very small and accurately determined forces are required to test mounts having slight, fragile filaments, and because test forces very near the rupture strength of the filament 7 are required to give most satisfactory test conditions. A further advantage of the apparatus appears in the manner by which it increases the pressure of the test fingers 3 and 4 once the leads 8 and 9 have begun to spread. At such times, the initial looseness or other defeet in the mount 2 allows the levers 8 and 9 to bring the magnets 27 and 28 closer together so that they exert greater pull on each other. This feature of the apparatus also contributes to the speed of operation thereof and assures appreciable dislodgment of the leads 5 and 6 in every instance where a defective mount 2 is detected.

Although the effect of the test operation is to dislocate the leads 5 and 6 of the mount 2, a condition that can be observed, means are also provided in combination with the test apparatus for giving an alarm and otherwise actuating associated control apparatus when a defective mount 2 isdiscovered. The alarm, in the disclosure, is the lighting of the indicator lamp 31 (Fig. 4) and is given when the levers 8 and 9 move to such an extent that the test fingers 3 and 4 bend one or both leads 5 and 6 from position so that the ends of the electrical contact screws 32 and 33 on said levers 8 and 9, respectively, butt against each other. The electrical circuit completed by the contacts 32 and 33 connects the indicator lamp 31 to to the line source 34 of electrical current.

The discovery of a defective mount 2 by the disclosed apparatus also effects the release of said mount 2 from the head 2 and thereby completes the last step in an operation effecting the completely automatic inspection of said mount 2. This operation is controlled in the same manner as the alarm by the making of an electrical circuit between the contacts 32 and 33 and effects the release of the mount 2 when said contacts 32 and 33 connect the solenoid 35 to the line 34 and thereby cause it to actuate means engaging the head 2'. The solenoid 35 is permanently mounted opposite the work station occupied by the head 2 (Fig. 1) and, when energized, causes the armature 36 to swing the lever 37 about the pivot pin 38 to a position where the roller 39 engages and then turns the jaw control arm 40 of the head 2. This movement counteracts the pressure of a torsion spring 41 bearing against a post 42 depending from the control arm 40 and turns said arm-40 in a direction whereby the lower and upper movable jaws 43 and 44 are spread from their gripping relation to respective lower and upper fixed jaws 45 and 46 to release the stem 47 and exhaust tube 48, respectively, of said mount 2. The control arm 4% effects motion in jaw 43 in the first portion of its travel since both are mounted on opposite ends of a shaft 49 extending through the hollow center column 50 of the head 2' and effects motion in the jaw 44 when the post 42, which extends through a slot 51 in jaw 46, bears against the inner edge of the jaw 44 and turns it about the post 52. The released mount 2 falls from the head 2' by its own weight.

In instances where the mount 2 is not defective, it continues to be retained by the head 2' and passes from operative relation to the test apparatus in the regular order of operation. Before the mount 2 advances, however, the test fingers 3 and 4 move back into butting relation to each other and then retract to one side of the path of movement of the head 2'. These latter operations of the test apparatus are brought about by the return motion of the connecting rod 23. The advance of the head 2', on the other hand, is brought about by the bracket 53 (only partially shown) which is one link of a carrier also responsible for effecting the advance of a second head 2' and another mount 2 (not shown) to working relation to said test apparatus in preparation for a succeeding cycle of operation thereof.

Although a particular embodiment of my invention has been shown and described by way of illustrating the invention, it will be obvious to those skilled in the art that various modifications may be made in the construction and arrangement of parts within the spirit of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for testing mounts of the class described having a filament connected across and between parallel spaced lead-in wires and comprising a pair of finger members inse-rtable between said lead-in wires, a pair of levers supporting said fingers at adjacent proximate ends thereof, means mounting said levers for pivotal movement to spread the finger members laterally of and against the lead-in wires, and a pair of magnets mounted on the remote ends of said levers with the end faces of unlike poles in closely spaced relation and so that they face and attract each other to urge the finger members apart and against the lead-in wires with progressively increasing force tending to displace said wires in case the filament is ruptured or defectively connected thereto.

2. Apparatus for testing mounts of the class described having a filament connected across and between parallel spaced lead-in wires and comprising a. pair of finger members inscrtable between said leadin wires,,a pair of levers supporting said fingers at adjacent proximate ends thereof, means mounting said levers for pivotal movement to spread the finger members laterally of and against the lead-in wires, and a pair of magnets mounted on the remote ends of said levers with the end faces of unlike poles in closely spaced relation and so that they face and attract each other to urge the finger members apart and against the lead-in Wires with progressively increasing force tending to displace said wires in case the filament is ruptured or defectively connected thereto, and intermittently operable means for retracting the said levers against the attraction force of said magnets to close said finger members for withdrawal of the mount.

3. Apparatus for testing mounts of the class described having a filament connected across and between parallel spaced lead-in wires and comprising a pair of finger members insertable between said lead-in wires, a pair of levers supporting said fingers at adjacent proximate ends thereof, a base member carrying said levers, means mounting said base member for movement to and from an operative position to advance the finger members to a position between the lead-in wires, means mounting said levers on said base member for pivotal movement to spread the finger members laterally of and against the lead-in wires, and a pair of magnets mounted on the remote ends of said levers with the end faces of unlike poles in closely spaced relation and so that they face and attract each other to urge the finger members apart and against the lead-in wires with progressively increasing force tending to displace said wires in case the filament is ruptured or defectively connected thereto, and intermittently operable means for retracting the said levers against the attraction force of said magnets toclose said finger members for withdrawal of the mount.

4. In testing apparatus of the class described the combination with means for fixedly supporting a mount having a filament connected across and between generally parallel spaced lead-in wires, of a finger member, means mounting said finger member adjacent said supporting means for movement towards and from as well as laterally of the mount for insertion of the finger between said lead-in wires upon such first mentioned movement, said mounting means being provided with a portion of magnetic material, and actuating means including magnet means mounted to effect movement of said finger member laterally of and against a lead-in wire by magnet attraction forces acting on the magnetic portions of said mounting means to urge said finger member against the lead-in wire with progressively increasing force tending to displace said lead-in wire in case the filament is ruptured or defectively connected thereto.

5. In testing apparatus of the class described, the combination with means for fixedly supporting a mount having a filament connected across and between generally parallel spaced lead-in wires, of a pair of finger members, lever members supporting said finger members, means mounting said lever members for movement of the finger members toward and from the mount for insertion thereof between the lead-in wires and also mounting said lever members for pivotal movement to spread the finger members laterally of and against said lead-in wires, said lever members being provided with a portion of magnetic material, and means including magnet members mounted to effect pivotal movement of said lever members to carry said finger members against said lead-in wires by magnetic attraction forces acting on the magnetic portion of said lever members to urge said finger members against the lead-in wires with progressively increasing fo-rce tending to displace said lead-in wires in case the filament is ruptured or defectively connected thereto.

References Cited in the file of this patent UNITED STATES PATENTS 1,583,877 Hahnemann et a1. May 11, 1926 1,708,359 Coune Apr. 9, 1929 2,174,254 Black Sept. 26, .1939 2,279,076 Sutton Apr. 7, 1942 2,292,235 McCarthy Aug. 4, 1942 2,329,599 Flaws, Jr. Sept. 14, 1943 2,563,881 Steadman Aug. 14, 1951 

